Constant pressure pumping apparatus



Feb. 14, 1961 J, F, WEm ETAL 2,971,470

CONSTANT PRESSURE PUMPING APPARATUS Filed Aug. 3, 1955 United States lCONSTANT PRESSURE PUMPING APPARATUS .lohn F. Wein and Samuel I. Wendell,Indianapolis, Ind., assignors to Stewart-Warner Corporation, Chicago,lll., a corporation of Virginia Filed Aug. 3, 1955, Ser. No. 526,100

8 Claims. (Cl. 103-150) The present invention relates to liuid pumpingapparatus, and particularly to pumps suited for supplying fuel tocombustion heaters or the like.

One object of the invention is to provide an improved pump assemblycapable of supplying iiuid at a regulated output pressure by means of ahighly simplified yet durable pumping structure.

Another object is to provide a fluid pump of exceptionally economicalconstruction capable of operating dependably over a long useful life.

Other objects and advantages will become apparent from the followingdescription of the form of the invention shown in the drawing in which:

Figure 1 is a side view of pumping apparatus incorporating theinvention, certain parts being broken away for clearness inillustration;

Fig. 2 is a sectional view taken generally along line 2-2 of Fig. 1 andshowing the connection of inlet and outlet lines to the apparatus; and`Fig. 3 is a detail view showing the lower side of the pumpingdiaphragm.

As shown, the apparatus comprises a central body or casing sectionformed as a generally rectangular casting. The lower side of the body iscentrally recessed to form a downwardly facing concave surface defininga cavity 14, Fig. 2. The lower side of this cavity is covered by arectangular diaphragm 16 of a synthetic rubber, preferably Buna N, thusforming a pumping chamber (also denoted by the numeral 14). The marginaledge of the diaphragm 16 is held by a centrally apertured plate 18tightly against a fiat surface 20 on the body 10 and protected by aflange 22 extending downwardly from the body into engagement with theplate. A raised bead 24 integral with the peripheral edge of thediaphragm locks into a rectangular groove Z6 formed in the body 10 atthe outer edge of the surface 20.

A shallow working clearance 28 is provided between the portion of thediaphragm 16 covering the cavity 14 and the plate 1S by relieving theopposed upper surface of the plate. A relatively narrow, rectangularopening 30 cut through the central portion of the plate 18 receives aT-shaped connecting head 32 extending downwardly from `the centralportion of the diaphragm 16.

The T-shaped head 32` is formed on the lower end of a tapered base 36integral with the fiat body portion 37 of the diaphragm 16. The base 36is elongated rectangularly in the same direction as the diaphragm body37. See Fig. 3.

p The connecting head 32 and its base 36 as well as the main portion ofthe diaphragm 16 `integral with the base are fashioned from Buna N or anequivalent material.

The diaphragm is formed in a manner such that the body portion 37 of thediaphragm extending from the base 36 is relatively exible, having ahardness of the order of 35 to 45 durometer. The head 32 `and base 36have` a greater hardness, approximately 70 to 80 durometer.

Thelconnecting head 32 depends into a lower casing section 38 heldtightly against the lower side of the plate ICO 18 by four assemblyscrews 40, Figs. 1 and 2, extending downwardly through a cap 42 on thetop side of the body 10 and through the body 10, passing through fourholes 44 in the diaphragm 16, as shown :in Fig. 3.

Two horizontally spaced bearings 46 mounted in the lower casing section38, Fig. 1, in axial alinement with each other support a horizontaloperating shaft 48 below the connecting head 32 on the pumping diaphragm16. An operating cam 50 eccentrically formed on the shaft 48 between thebearings 46 is encircled by a cylindrical cam follower 52 having afiattened top portion 54 which abuts against the flat underside of theconnecting head 32, Fig. 2. Two legs 56 extending upwardly from oppositesides of the cam follower 52 straddle the connecting head 32longitudinally along the latter, forming a yoke-like connection with theT-shaped head 32. The respective legs 56 define two toes or lugs 58fitting closely over opposite ends of the head and abutting snuglyagainst the sloping ends of the tapered base 36.

Two brackets 60 on the lower casing section 38 are adapted to mount theassembly on a power source (not shown), such as an internal combustionengine. The drive shaft 48 can be connected to rotating parts of theengine in any suitable manner.

Liquid in a line 62 leading, for example, from a gasoline tank (notshown) is supplied to the pumping charnber 14 through an elbow fitting64 threaded into an enlarged bore 65 in the body 10, an inlet valve 66in the bore 65, and an L-shaped bore 68 extending from the valve to thepumping chamber.

The inlet valve 66 itself is separately fashioned as a self-containedcartridge inserted in the bore 65 ahead of the fitting 64 and heldagainst an apertured seal 70 `on the bottom of the bore 65 by acompression spring 72 interposed between the valve and the fitting. Asshown, the valve comprises an apertured disc 74 fitted into the outerend of a counterbored sleeve 76 and secured in place by crimping theadjacent marginal edge of the sleeve. A valve disc 78 is pressed againstthe downstream face of the disc 74 by a light compression spring 80contained within the sleeve 76.

Fluid is pumped from the chamber 14 out through a bore 82, a dischargecheck valve 84 mounted in an outlet bore 85 connecting with the bore 82,and a fitting 86 threaded into the body 10 and connected with a line 88leading to a combustion heater or the like (not shown). Structurally thedischarge check valve 84 is similar to the inlet check valve 66, thedischarge valve being reversed end for end to permit one-way ow of fluidfrom the pumping chamber 14. The mountings for the two valves 66 and 84in the two bores 65 and 85 are similar.

The upper side of the body 10 is shaped to form a rather deep, upwardly`open recess connected at its lower end to the outlet bore 85 through abore and slot passageway 92 communicating with the outlet bore at thedownstream side of the valve 84. The upper end of the recess 90 iscovered by a flexible diaphragm 94 held in place by the cap 42.

Thus covered, the recess 90 forms-a regulator chamber which uponoperation of the pump assembly is filled with fiuid at the outletpressure of the pumping chamber 14. The force of uid pressure acting onthe underside of the diaphragm 94 is opposed by a compression spring 96engaging a spring seat 98 on the upper side of the diaphragm 94 andextending upwardly into a downwardly open adjusting screw 100 threadedinto the cap 42.

Vertical movement of the regulator diaphragm 94 in Aopposition to thespring 96 controls a relief valve 102 Patented Felb. 14, 1961 wardlyinto interconnected exhaust bores 112 in the body leading into the bore65 at the upstream side of the inlet valve 66.

In the operation of the pumping assembly thus formed, the diaphragm 16is positively reciprocated (with some lateral llexure) by tne eccentriccam 50 connected to the-diaphragm through the follower 52 and theconnecting head 32. Fluid is drawn into the pumping chamber 14 throughthe inlet valve 66 and forced out through thedischarge valve 84 underincreased pressure.

' The positively operating pump thus formed is quite simplestructurally, comprisingressentially inlet and discharge valves, arubber diaphragm, a cam actuator and a cam follower connected to thediaphragm by means of a rubber connecting head integral with thediaphragm. There is no need to reinforce the pumping diaphragm byseparate reinforcing discs or the like. A sturdy connection between thecam follower and the connecting head transmits to the diapnragmreversing forces for positively lreciprocating the diaphragm in oppositedirections over a longservice life.

The output pressure of theV pump is prevented from exceeding anadjustable predetermined level by opening of the relief valve 102 by thepressure responsive actuator structure connected to the downstream sideof the pump outlet valve 84. Regulation of the controlled outputpressure of the pump requires merely a simple adjustment ofthe screw 100to vary the stress on the spring 96. The pumping assembly thus providedis capable of producing a highly satisfactory and dependable pumpingaction throughout a long service life.

Y The word irregular in the claims as applied to the surfaces of thehead of the diaphragm extension and the mating portion of the pumpactuator refers to a peripheral surface having a cross-section which isnonuniform. That is the surface is not parallel with the directionv ofmotion.

While we have shown and described a preferred embodiment of ourinvention, it will be apparent that variations and modifications thereofmay be made without departingfrom the principles and scope of theinvention. We therefore desire, by the following claims, to include allsuch variations and modifications by which substantially the results ofour invention may be obtained through the use of substantially the sameor equivalent means.

We claim:

1. In a fluid pump of the type in which a substantially flat diaphragmof rubberlike material reciprocates in a pumping chamber to draw liuidfrom a source into the chamber by Way of an inlet check valve and toexpel the fiuid from the chamber by way of an outlet check valve, thecombination with the diaphragm of an actuator assembly comprising athickened central portion on one side of the diaphragm forming aconnecting base extending away from the pumping chamber, a connectinghead integrally formed on the outer end of the base and extending awayfrom the pumping chamber the head defining an irregularly shaped surfacein the direction extending away fromthe chamber in the line of movementof said diaphragm, the connecting head and base being formed of the samerubberlike material as the diap hragm and hardened to a degree greaterthan the hardness of the portion of the diaphragm encircling the base,and a'reciprocable actuator defining a corresponding irregular surface4embracing the headV andV engaging said 44 connecting base to impartreciprocable pumping motion thereto.

2. In a fiuid pump of the type in which a substantially fiat diaphragmof rubberlike material reciprocates in a pumping chamber to draw iiuidfrom a source into the chamber by way of an inlet check valve and toexpel the fluid from the chamber by way of an outlet check valve, thecombination with the diaphragm of an actuator assembly comprising athickened central portion on one side of the diaphragm forming aconnecting base extending away from the pumping chamber, a T-shapedconnecting head integrally formed on the outer end of the base andextending awayV fromV the pumping chamber, the connecting head and basebeing formed of the same rubberlike material as the diaphragm andhardened to a degree greater than the hardness of the portion of thediaphragm encircling the base, and a reciprocable actuator defining aT-shaped recess, embracingthe T- shaped head andengaging said connectingbase; to impart reciprocable pumpinglmotion thereto.

3. In a fluid pump ofthe type in which a substantially fiat diaphragm ofrubberlike material reciprocates in a pumping chamber` to draw liuidfrom a source into the chamber by way of an inlet check valve and toexpel the liuid from the-chamber by way of'an outlet check valve, thecombination with the diaphragm of an actuator assembly comprising athickened central diaphragm portion forming a tapered connecting base onone side of the diaphragm and extending away from the chamber, anirregularly shaped extension of the connecting base defining aconnecting head at the outer end of the tapered base, a reciprocablepump actuator including a pair of spaced legs formed to embrace theconnecting head and to firmly engage the tapered base for impartingreciprocable pumping motion to the diaphragm.

4. In a fiuid pump of the type in which a substantially fiat diaphragmof rubberlike material reciprocates' in a pumping chamber to draw liuidfrom a source into the chamber by way of an inlet check valve and toexpel the fluid from the chamber by way of `an outlet check valve, thecombination with the diaphragm of an actuator assembly comprising athickened central diaphragm por-` tion forming a tapered connecting baseon one side of the diaphragm and extending away from the chamber, anextension of the connecting base defining a T-shaped connecting head atthe outer end of the tapered base, a reciprocable pump' actuatorYincluding a pair of spaced legs formed to embrace the connecting headand to firmly engage the tapered base for imparting reciprocable pumpingmotion to the diaphragm.

5. The combination claimed in claim 4 wherein the connecting head andbase are formed of the same rubberlike material as the diaphragm andhardened to a degree greater than the hardness of the portion ofthediaphragm encircling the base.

6. For use in a fiuid pump, a reciprocable diaphragm and actuatorVassembly comprising a substantially at diaphragm body formed of ahardenable rubberlike material, the central portion of they diaphragmbody being thickened to form a tapered connecting base integral with oneside of the diaphragm body and extending laterally therefrom, anirregularly shaped connecting head integrally formed on the outer end ofthe tapered base and extending away from the diaphragm body, theconnecting head and the tapered base being formed of the same `materialas the diaphragm body and hardened to a'degree greater than the hardnessof the diaphragm body surrounding the base, a reciprocable pump actuatordefining a corresponding irregular surface embracing the head and firmlyengaging the tapered base to impart reciprocable pumping motion to thediaphragm.

7. For use in a fluid pump, a reciprocable-diaphragm and actuatorassembly comprising a substantially fiat diaphragm body formed 4of ahardenable rubbermaterial, the central portion of. the diaphragm bodybeingthickened to form a tapered connecting base integral with one sideof the diaphragm body and extending laterally therefrom, a T-shapedconnecting head integrally formed on the outer end of the tapered baseand extending away from the diaphragm body, the T-shaped connecting headand the tapered base being formed of the same material as the diaphragmbody and hardened to a degree greater than the hardness of the diaphragmbody surrounding the base, a reciprocable pump actuator defining aT-shaped slot receiving and embracing the T-shaped head and the taperedbase to impart reciprocable pumping motion to the diaphragm.

8. For use in a iluid pump, a reciprocable diaphragm and actuatorassembly comprising a substantially ilat diaphragm body formed of ahardenable rubber material, the central portion of the diaphragm bodybeing thickened to form a tapered connecting base integral with one sideof the diaphragm body and extending laterally therefrom, a T-shapedconnecting head integrally formed on the outer end of the tapered baseand extending away from the diaphragm body, the T-shaped connecting headand the tapered base being formed of the same material as the diaphragmbody and hardened to a degree greater than the hardness of thediaphragmbody surrounding the base, a rotary cam operator mounted intransverse relation to the connecting head, a reciprocable cam followercarried by the operator and including a pair of spaced legs embracingthe T-shaped head and iirmly engaging the tapered base to impartreciprocable pumping motion to the diaphragm.

References Cited in the le of this patent UNITED STATES PATENTS1,610,950 Johnston Dec. 14, 1926 2,191,458 Duden Feb. 27, 1940 2,267,280Kuhnel Dec. 23, 1941 2,415,060 Craig Jan. 28, 1947 2,575,398 SchroederNov. 20, 1951 2,641,283 Houston June 9, 1953 2,642,090 Barr June 16,1953 2,645,414 Maierhofer July 14, 1953 2,658,526 Porter Nov. 10, 19532,685,304 Wright Aug. 3, 1954 2,690,295 Rand Sept. 28, 1954 2,782,719Georgias Feb. 26, 1957 FOREIGN PATENTS 113,019 Switzerland Dec. 16, 1925463,671 Great Britain Apr. 5, 1937

